package org.bouncycastle.asn1;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.Vector;

import org.bouncycastle.util.encoders.Hex;

public abstract class ASN1OctetString extends ASN1Object implements ASN1OctetStringParser {
    byte[] string;

    /**
     * return an Octet String from a tagged object.
     * 
     * @param obj
     *            the tagged object holding the object we want.
     * @param explicit
     *            true if the object is meant to be explicitly tagged false otherwise.
     * @exception IllegalArgumentException
     *                if the tagged object cannot be converted.
     */
    public static ASN1OctetString getInstance(ASN1TaggedObject obj, boolean explicit) {
        return getInstance(obj.getObject());
    }

    /**
     * return an Octet String from the given object.
     * 
     * @param obj
     *            the object we want converted.
     * @exception IllegalArgumentException
     *                if the object cannot be converted.
     */
    public static ASN1OctetString getInstance(Object obj) {
        if (obj == null || obj instanceof ASN1OctetString) {
            return (ASN1OctetString) obj;
        }

        if (obj instanceof ASN1TaggedObject) {
            return getInstance(((ASN1TaggedObject) obj).getObject());
        }

        if (obj instanceof ASN1Sequence) {
            Vector v = new Vector();
            Enumeration e = ((ASN1Sequence) obj).getObjects();

            while (e.hasMoreElements()) {
                v.addElement(e.nextElement());
            }

            return new BERConstructedOctetString(v);
        }

        throw new IllegalArgumentException("illegal object in getInstance: " + obj.getClass().getName());
    }

    /**
     * @param string
     *            the octets making up the octet string.
     */
    public ASN1OctetString(byte[] string) {
        this.string = string;
    }

    public ASN1OctetString(DEREncodable obj) {
        try {
            ByteArrayOutputStream bOut = new ByteArrayOutputStream();
            DEROutputStream dOut = new DEROutputStream(bOut);

            dOut.writeObject(obj);
            dOut.close();

            this.string = bOut.toByteArray();
        } catch (IOException e) {
            throw new IllegalArgumentException("Error processing object : " + e.toString());
        }
    }

    public InputStream getOctetStream() {
        return new ByteArrayInputStream(string);
    }

    public ASN1OctetStringParser parser() {
        return this;
    }

    public byte[] getOctets() {
        return string;
    }

    public int hashCode() {
        byte[] b = this.getOctets();
        int value = 0;

        for (int i = 0; i != b.length; i++) {
            value ^= (b[i] & 0xff) << (i % 4);
        }

        return value;
    }

    boolean asn1Equals(DERObject o) {
        if (!(o instanceof ASN1OctetString)) {
            return false;
        }

        ASN1OctetString other = (ASN1OctetString) o;

        byte[] b1 = other.string;
        byte[] b2 = this.string;

        if (b1.length != b2.length) {
            return false;
        }

        for (int i = 0; i != b1.length; i++) {
            if (b1[i] != b2[i]) {
                return false;
            }
        }

        return true;
    }

    abstract void encode(DEROutputStream out) throws IOException;

    public String toString() {
        return "#" + new String(Hex.encode(string));
    }
}
